Spark plug shield



Dec. 4, 1951 H. w. CARSON SPARK PLUG SHIELD Filed Sept. 50, 1949 INVENTOR H 245) M CHI-7.90

772%Mflmm v Mm ATTORNEYS Patented Dec. 4, 1951 UNITED STATES PATENT ()FFICE 2,577,308. SPARK PLUG SHIELD Harley Carson, Caprock, N. Mex. Application September so, 1949, Serial No. 118,863

(01. lat-19s) 1 Claim.

This invention relates to spark-plug shields, and more particularly to a shield for the spark plug of a single cylinder, horizontal-type, internal combustion engine,'such as is frequently used in the open to drive oil-well pumps and for similar purposes.

It is among the objects of the invention to provide a spark-plug shield which can be quickly and easily attached to an engine with no material modification of the engine structure and can be manually moved without detaching it from the engine between a spark-plug enclosing or covering position, and a position in which it is entirely free of the spark plug for removal, replacement, or adjustment of the spark plug, which effectively protects the spark plug from moisture due to atmospheric precipitation or condensation and, at the same time, provides adequate ventilation to keep the spark plug from over-heating, and which is simple and durable in construction, economical to manufacture, and does not interfere, in any way, with the operation of the engine.

Other objects and advantages will become apparent from a consideration of the following description and the appended claim in conjunction with the accompanying drawing, wherein:

Figure 1 is a side elevation of a fragmentary portion of the internal combustion engine showing a spark-plug shield, illustrative of the invention, operatively applied thereto;

Figure 2 is a side elevation of the spark-plug shield on a somewhat enlarged scale;

Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 1;

Figure 4 is an enlarged end view taken from the left of Figure 1.

With continued reference to the drawing, the engine illustrated has a cylinder 5 and a cylinder head 6 secured on one end of the cylinder by cylinder head bolts as indicated at I and nuts, as indicated at 8, threaded one onto each bolt. A spark plug pocket 9 of partially cylindrical shape is provided in the cylinder head and opens to the outer end and to the side of the cylinder head. A spark plug 20 is disposed in the pocket 9 and is shielded at one side by the wall of the pocket. An apertured plate or washer I is attached to the engine by one of the engine headbolt nuts, a shield ll of thin-walled material is pivotally secured to the plate at one end by a headless screw l2 having wing nuts l3 and I4 threaded thereon, and a hand-knob I is secured to the shield at a location spaced from the end of the shield pivotally connected to the plate ID.

The plate or washer It! may be an apertured disc, as clearly illustrated in Figure 3, having an aperture of suflicient size to receive an engine head bolt 1, and this plate is secured to the engine by inserting an engine head stud bolt located adjacent the pocket 9 through the aperture in the plate and then tightening the associatednut down onto the plate or washer. This washer or plate is provided, at a location spaced from the aperture receiving the engine head bolt, with a smaller aperture through which the screw l2 extends.

The shield I l is a member of thin-walled material, such as sheet metal, synthetic resin plastic or compressed fibre, and comprises two walls l6 and I1 disposed substantially at right angles to each other.

The wall I! has an arcuately-curved, outer edge I8 of a contour which is substantially the same as the shape of the open end of the sparkplug-receiving pocket or recess 9 in the cylinder head 6 of the engine, and this wall has, at one end, 2. depending tongue 2| separated from the wall l6 by an arcuately-curved notch 22 and apertured to receive the screw 12 for pivotally attaching the shield to the plate or washer Ill. The wall 16 is generally rectangular in shape to overlie the outer or open side of the spark-plugreceiving pocket or recess in the engine cylinder head, but has a curved extension 23 at the end thereof adjacent the tongue 2|, and at its side remote from the wall ll, the purpose of this tongue being to direct ventilating air to the interior of the shield and into the spark-plug-receiving pocket in the cylinder head. The walls [6 and I! terminate somewhat short of the upper side of the spark-plug-receiving pocket to provide an air-outlet opening at the upper end of the shield when the shield is in its operative, spark-plug covering position. This arrangement provides adequate ventilating air to prevent the spark plug from over-heating while, at the same time, eifectively shielding the spark plug from moisture due to atmospheric precipitation or condensation even when such moisture is driven against the engine by a high wind.

With the shield in its spark-plug covering position, if it is desired to have access to the plug to change the plug, or for other purposes, it is necessary only to grasp the handle [5 and swing the shield outwardly so that it completely clears the spark-plug-receiving pocket in the cylinder head. The frictional resistance to movement of the shield can be adjusted by tightening or loosening the wing nuts I3 and M on the screw [2 and the shield can be effectively locked in spark-plug covering position by firmly tightening these wing nuts.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is, therefore, to be considered in all respects as illustrative and not restrictive, 'the scope of the invention being indicated by the appended claim ratherthan by the foregoing: description, and all changes which come within the meaning and range of equivalency of the claim are, therefore, intended, to be embraced therein.

What is claimed is: p

In combination with an engine cylinder head having a spark plug receiving pocket of partly cylindrical shape opening to the outer end and the side thereof, a cylinder head bolt located adjacent said pocket, and anut threaded onto said bolt, a spark shield assemblycomprising a plate having a first aperture receiving said cylinder head bolt and a secured aperture spaced from said first aperture, said plate being clamped between the corresponding nut and the cylinder head, a pivot screw in said second aperture, and a shield secured at one end to said plate by said pivot screw, said shield comprising a body of 4 thin wall material having two walls disposed substantially at right angles to each other, one of the walls of said shield being adapted to cover the outer open end of said pocket and having a curved edge remote from the other of said walls contoured to fit the shape of the outer open end of the spark plug receiving pocket in the cylinder head and having at one end a depending apertured tongue receiving said pivot screw, and the: other wall of said shield being of generally rectangular shape and adapted to cover and partly close the side of said spark plug receiving pocket but having a width somewhat less than the: width of the open side of said pocket to provide for the passage of ventilating air into and out of said pocket.

' HARLEY W. CARSON.

' REFERENCES CITED The following references are of record in the file of this patent:-

Number Name Date 25 1,353,959 Holst Sept. 28, 1920 1,511,001 Padden Oct. '7', 1924 1,619,524 Manchester nu--- Mar. 1, 1927 

